But first, Hudson and Zito will face off Saturday before both head into their planned retirements, and they will do it right back where their big league careers began, at the Oakland Coliseum. What a nostalgic moment this will be, even if it only lasts for a few innings.

''It'll be cool just to be on the same field with him,'' Hudson said. ''We hung out for a little bit in spring training and caught up a little bit. It'll be nice to see him in an A's uniform again. I know it's something I think it'd be special. I hope that he'd probably feel the same way.

''It's going to be really cool to get back out there and pitch at a place where my career started.''

They each have pitched on both sides of the bay, Hudson with a nine-year detour to Atlanta before he signed with San Francisco for $23 million in November 2013. Zito took last season off after completing a $126 million, seven-year deal with the Giants, then came back this year with the A's.

''It's awesome,'' Giants CEO Larry Baer said.

Zito pitched at Triple-A Nashville all season with a stint on the disabled list.

''Did he need to go down to Triple-A and travel through those road trips you have to go on, whether it's buses or getting up at 4 in the morning to catch a plane? No, he didn't,'' Giants manager Bruce Bochy said. ''But he loves baseball. He still had it in his blood and he wanted to give it one more shot and felt like he still had the stuff to do it, and here he is in the big leagues. Good for him.''

Hudson finally won a World Series ring last season with San Francisco. Zito got his two in 2010 and `12 for the Giants, playing a key role in the second championship after being left off the roster entirely for the first title run.

The 40-year-old Hudson has spent some time appreciating every moment this season, the ups and the downs. The Giants will honor him during their last homestand.

''It's been a year of a lot of reflection,'' Hudson said. ''I've known for a while that this is going to be it. I've taken this year and really focused on things that are going to be really special to me. I'm sure after I'm done playing, I'll have a chance to reflect on my whole career.''

The 37-year-old Zito won the 2002 AL Cy Young Award with Oakland and went 102-63 with a 3.53 ERA over seven seasons with the A's before joining the Giants in December 2006.

The left-hander with that nasty curveball delivered two crucial wins during San Francisco's 2012 World Series run. He earned a victory in Game 5 of the NL Championship Series against the Cardinals at Busch Stadium facing elimination, then in the opener at home of a World Series sweep against Detroit.

''It's great when you think about the game and how those two have been some pillars for the Bay Area,'' Giants reliever Javier Lopez said. ''To see those two finish their career, it's going to be a special time for everyone involved and particularly the teammates that have been able to play with them.''

By the time the A's promoted Zito on Sept. 16, he had gone home - he figured his chance was over to reach the big leagues this year. Newly promoted Giants infielder Kevin Frandsen had bought a ticket to be in the stands Saturday, but now he will have a better seat in the dugout.

''When you do what Barry Zito's done in the Bay Area and for the Oakland Athletics, I never understood that there was any question to why he wouldn't come up and throw his last pitch as an Oakland A,'' Giants pitcher Jake Peavy said.

Hudson and Zito have 387 career wins between them - and those combined three World Series rings. Mulder won 103 games in nine years and was done after 2008.

''It definitely was fun to watch Huddy go out, Mulder go out and do their thing,'' Zito said. ''We all did it in different ways. Mulder was the king of the 2-hour game, Huddy would just go out there with his sinker-split, punching guys out left and right. I had the curveball and the changeup. We definitely enjoyed watching each other.''

A's third base coach Ron Washington can't wait to see the special reunion.

''When we started putting things together here in Oakland in the early years when I was here in the `90s, they were the backbone of it,'' Washington said. ''We knew every night we had a chance to win.''